Method of comparing sounds.



C. M. HECK.

METHOD 0F COMPARiNG SOUNDS.

APmcArloN man JULY 1. w15.

Patented Nov. 2, 1915.

2 SHEETS-SHEET l- @LAM INVENTOR.

'ATTOM C. M. HECK.

METHOD 0F COMPARlNG SOUNDS. APPLICATION m50 luLY 1. 1915.

1,1 559,023.v Patented Nov. 2, 1915.

2 SHEETS-SHEET 2,

ma l8o 5a V v 5l INVENTOR. lm/h1.

BY {vk-95' ATNEY iss. acoustics,

CHARLES M. HECK, OF RALEIGH, NORTH CAROLINA.

METHOD OF COMPARING SOUNDS.

Specification of Letters Patent.

Patented Nov. 2, 1915.

Original application filed February 5, 1915, Serial No. 6,316. Divided and this application filed July 7, 1915. Serial No. 38,455.

To all whom. it may concern.' Y

Be itlinown that I, CHARLES M. HECK, a citizen of the United States, residing at Raleigh, in the count)1 of lValie and State of North Carolina, have invented new and useful Improvements in Methods of Comparing Sounds, of which the following is a specification.

This invention' relates to the art of sound detection and comparison.

In all observations made by the senses, impressions on the brain rapidly lose their intensity and character, the memory being thus unable to compare sensations following each other at relatively long intervals. In observations on light, some hundred fold increase of accuracy has been attained by utilizing instruments that will place two lights to be Vcompared before thel eyes at the same time, or one `light after another in rapid succession.

One of the objects of the present invention is to accomplish a similar result in connection with sound observation, whereby the detection and investigation of sounds, the resonant properties of bodies, and the reflecting and absorbing quantities, may be more accuratelyT conducted than has heretofore been possible.

A further object is to provide for etlicient .comparisonof sounds by equalizing the vol-v T'he invention will be hereinafter fully set,

forth and particularlyT pointed out'in the claims.

ln the accompanying drawing: Figure i is a view of a stethoscope constructed in accordance with my invention. Fig. Q is an enlarged detail view illustrating the sound equalizing device. Fig. 3 is an end view thereof. Fig. 4 is a diagrammatic transverse sectional view thereof. Fig. 5 .is an enlarged det-ail view of one of the receiving device. Fig. "i

chambers. Fig. 6 is a detail of the locking is a detail view of a. slight modification. F ig. S is a diagrammatic view illustrating one of the uses of my invention. veferring to the drawing, the instrumen illustrated in Fig. l is a convenient form of the doctor`s stethoscope, although it will appear later that the instrument is not limited to medical work. The stethoscope illustrated comprises the ear nipples 10, connected with tubes l1 leading from the arms 12 of a coupling 13. Said coupling is provided with lower branches 14 from which tubes 15 lead to the cups 1G, designed to receive the sound in the well known manner. For con-l venience, the cups 1G, and tubes 15, may be called receiving members, and the tubes 1l and ear pieces 10, delivery members. VSaid cups 1G may also be technically sound directing devices, for the reason lthat they perform the function of directing sounds received by them.

Rotatabl)7 supported by the coupling '13, and preferably by the branches 1%, is a valve member 17 provided with openings 1S and 19, arranged at an angle with respect to each other, and located so as to control the passage of soundwaves through saidV branches 21st. `The openings 1S andlf) are ar anged as shown in Fig. 4f, it being apparent from said figure that either tube may be open when the other is closed, or both open to the.

same extent at the same time, or one full open and the other open to any desired fraction. An indi ating scale :20 mounted on one of the tubes 1l, acting also as a cap to hold the valve member 17 in position, is provided, said cap being attached in suitable manner. The end of the valve member is provided with a head 22 having a pointer 23 cooperating with the scale to indicate the adjustment of the valve. By the use of this arrangement, the valve member may 'bc adjusted so that the volume of sound passing from branches 1l to the arms 12 will be equalized, rendering it possible to determine the nature of the respective sounds without. regard to any difference in volume at thc source. Thus two sounds of dillerent volumes may be equalized as to the volume by adjusting the valve member so that the openings 1S and l0 will equalize ani.Y difference in the volume. 4

The receiving cup or mou-th piece 16 may be of any suitable or desirable construction.. It is preferred however, to make them in two sections. One of said sections comprises a shutter chamber 2l provided with a neck 25 to enter the ,tube 15. Located within said chamber is a pivoted shutter or valve 26 heavy enough to shut off sound tending to pass through said chamber. The shutter or diaphragm Q6 is provided with a milled head '27 by which it may be rotated, but is normally held in its closed position against shoulders 2S by means of a spring 29. When the shutter is opened and released the spring QQ causes the same to fly back to shut position. To preventa noise as the shutter is closed, an insulated stop 30 is placed outside of the chamber 24C to engage the head 2T, and thereby limit the movement of said shutter. Should it be desired to lock the shutter inv open position, a spring latch 31 is provided having a finger adapted to engage an. opening 32 in the head27.

The mouth piece is detachably connected to the shutter chamber 2l, in any suitable manner, as the threaded portion 33. For ordinary sound observation in connection ivith the usual medical use of a stethoscope, the cups may be of the usual type. For percussion testing however, a cup is employed in which is secured a leaf spring 35 to which is secured a suitable hammer 36, said spring being held vin position by a suitable sound insulated clamp 37. Projecting through an n opening in the Wall of the cup is a ratchet Wheel 38 rotatably supported by a leaf spring 39, which is also supported by a sound insulated clamp. The insulation comprises spaced apart felt-Washers connected by an intermediate felt tube through which the bolt of the clamp passes. A. suitable vcover lll maybe provided for the ratchet wheel, lin order to enable the cup to be used in the ordinary manner, if the percussion device is not to be utilized at any specific i time. In operation, the open end of the cupis placed upon the. surface of the body to be tested, and the hand holding the mouth piece has one finger on the ratchet and by rotating the' latter the teeth thereoiI successively engage the leaf spring and thus make a stroke with the hammer 36. Each time that the leaf spring is released by the ratchet, the' hammer BG will strike against the surface vvith `which the cup is in contact, and the character of the sound emitted by said surface, when struck by the hammer will, of course, vary with thenature of the body being tested. To increase the intensity of the stroke. the finger vvhile pushing the teeth forward presses the ratchet Wheel iiiivardly, thus elevating the spring a greater distance before its release. During the foregoing operation the' shutter 25 is held open. When it is desired to use the stethoscope Without the percussion oevice,

the cover 41 is placed in position, and the shutter :25 is opened and closed, as the operator may desire, by means of a finger engaging the milled head 27. I

In order to detect and determine the reiection and absorption of bodies with respect to sound. a mouth piece 40 is employed, as illustrated in Fig. 7.. Said mouth-piece provided with an internal clamping device 41 constructed to support a watch 42, or other similar sound producing device. The watch is thoroughlyT insulated against trans'- mission-ot' sound to the Wall of the cup by means of suitable packing 43, of felt or similar material. The reflector is best used with a wall 44, one side of which has a telt damper 4:5, said wall being so shaped as to pro` tect the shutter chamber from sounds that may come without first reflecting against the object 46, on which the mouth of the cup is placed.

All of the cups, shutter chambers. and other parts are preferably provided with an insulating covering, best illustrated in Fig. 7, soas to protect the parts of Ythe instrument from extraneous sounds such as produced by rubbing or striking the harder parts of the apparatus. Said insulation comprises an elast-ic 'covering such 'as sheet rubber, inclosing a loose sound absorb-- ing felt 4S.

It will be understood that While the rescope. Without departing from the spirit of -iny invention.

Y In Fig. 8 I have illustrated a method of comparing the diaphragms of sound reproducing machines to determine differences. in quality and character ot sound reproduction. Referring to said figure, and 51 indicate conventionally illustrated grapliophones, provided with the usual diaphragms supported in suitable manner as indicated at 52 and 53. The sound receiving cups or members -l are connected with the diaphragm supports 52, 53 and are provided With sound excluding shutters 55. Saidfreceiving cups or members are connected by tubes 5G with the branches 5T ot' a coupling member 5S, and a sound equalizing device 59 is preferably provided. The upper branches 60 of the coupling member are connected by tubes Gl ivith the delivery members (3'2- whicli are also provided with sound excluding shutters G2. Said delivery members performv the function of sound directingdevices. The shutters and 63 are Ysimilar in construction to shutters 26, and are provided with similar adjuncts.

In operation, the machines 50v and 5l. are

isi. ACOUSTIGB, g l" mi@ visual-:gg f

the two amplifying devices may be readilyn determined.

The apparatus above described forms the subject-matter of a co-pending application filed Feb. 1915, Serial No. 6316, this case being a division of said application.

Having thus explained the nature of my invention and described an operative manner of constructing and using the same, although without attempting to set forth all of the forms in which it may be made, or all of the forms of its use, what I claim is 1. The method of comparing sounds which consists in causing sound found at diiferent points to travel toy a common point.A only Copies of this patent may be obtained for through pre'e'stablished paths, controlling said sounds in said travel in suchwa `manner as to cause them to arrive substantially undiminished at said common point, and observing "said sounds at said common point separately. Y

2. The method of comparing sounds which consists in alternately permitting sounds to travel only through different prestablished paths to a common point, controlling the intensity of said sounds in travel, and observingsaid sounds arriving through eachof said paths separately. Y e

3. The method of comparing sounds which comprises permitting successively each of a number of simultaneously occurring 'sounds to pass only through prestablished paths` to a common point, and observing the variations through said succession at said `common point.

et. The method of comparing sounds which comprises successively permitting sounds occurring at different points to pass only through different prestablished paths to a common point, controlling the intensity of said sounds in said travel, and observing the variations through said succession at said common point. A

5. The method of comparing sounds which comprises successively permitting different sounds to pass through different preestablished paths to a common point, and caus-l tion from said common point to a point of 4 observation.

7. The method of comparing sounds which consists in successively permitting different sounds to pass through different prestablished paths to a common point, causing said sounds to take a common direction from said common point of observation, and controlling the volumes of said sounds in their travel.

8. The method of comparing sounds which consists in successively permitting sounds found at different points to pass through prestablished paths to a common point and causing said sounds to take a common direction to a point of observation, and controlling the volumes of said sounds in their travel. Y 1

9. The method of comparing sounds which comprises causing sounds found at different points to travel to a common point only through definite paths and varying the volunie of sound permitted to reach said common .point through one of said paths to equalize the intensity of the sound at said common point.

10. The method of comparing sounds which comprises causing sounds to reach a common point only through definite paths and varying the volume of sound permitted to reach said common point through either of said paths to equalize the intensity of sound at said common point.

11. The method of comparing sounds which comprises causing sounds found at different points to reach a common point only through deiinite'paths and varying the volumes' of the sounds admitted through each of said paths in such a manner as the volume of sound admitted through one path is increased in the same proportion as the volume admitted through the other path is diminished'.

In testimony whereof I have hereunto set my hand. il

CHARLES M. HECK.

five cents each, by addressing the Commissioner of Patents, Washington, D. C.

ioo 

